Severe natural disasters may isolate remote areas, forcing land transportation to be infeasible, necessitating emergency rescues by air. Safe and efficient flight plans for emergency logistics need consideration of geographical terrain, weather conditions, as well as the kinematic attributes of the vehicle to convey. Although existing three-dimensional routing methods consider winds and basic kinematics, transitional behaviors of helicopters, such as lag distance/time for acceleration, deceleration, and altitude adjustments, have yet to be considered in the network structure. Hence, this study designs a state-augmented route-finding algorithm that is capable of identifying the minimum-time flight route from a single origin to all accessible locations. The devised framework seeks a discrete state space comprising three-dimensional coordinates (East-West, North-South, and elevation) and a flight mode. Aerodynamic effects such as tailwind acceleration and headwind resistance can be considered while adhering to safety standards and operational requirements. For example, arriving at a destination site with a hover state is mandatory for immediate rescues. Numerical simulations were conducted for a hilly region spanning approximately 9 km  14 km. In a tailwind scenario, the optimized trajectory prioritized gaining altitude to attain a faster flight with the help of strong winds. The results showed that the total flight time was reduced by approximately 23% compared with a headwind scenario, along with a byproduct of longer travel distance. The state space comprised approximately  nodes, and the average computation time for optimization was approximately 6.6 seconds. The results highlight the applicability of the proposed methodology to prompt rescue logistics.

Keywords

Emergency logistics, helicopter conveyance, flight dynamics, state space and optimal path.